Details

Date

1877

Author

Pasteur

Contribution

a. Reported microbial causation of anthrax.

Reference

Carter

Notes

He induced anthrax in cattle by injecting filtered anthrax bacilli. He acknowledged Koch's prior isolation of the anthrax bacilllus, but Pasteur believed that he had shown that the bacillus was a sufficient cause whereas Koch had [only] shown it to be a necessary cause (always present, although sometimes only as spores). Carter says sufficiency was virtually ignored in Koch's 1876 paper. Koch, however, did inoculation experiments, and reported them in the 1876 paper -- so presumably Carter here refers to the charge that Koch had not entirely ruled out the possibility that some factor other than the bacillus was responsible for the anthrax in inoculated animals. Koch, however, had isolated the bacteria and grown them in ocular fluid through several passages, and shown that they were infective to mice. He also transmitted the disease serially in mice through eight passages (using pieces of spleen tissue). Pasteur had subsequently grown the bacillus in [a diluted-urine?] medium, and went through many high-volume serial dilutions to rule out the carry-over of any non-living factors. Was Carter too dismissive of Koch's demonstration of "sufficient" cause? Was the difference between the two studies merely quantitative -- a matter of dilution? Pasteur, additionally, showed absence of infection after injection of filtered blood. Davaine had already shown the effect of filtration per placenta [and Klebs by filter?]. Did Koch inject blood or tissue from non-infected animals and fail to get anthrax? If so, that would presumably have made his case even stronger. In any case, his inoculation experiments (together with his observations on bacteremia and spore formation) constituted good evidence that the bacteria were the cause of the disease. Certainly, and significantly, Koch's evidence was enough to convince influential leaders such as Cohn and Cohnheim. In the view of most Pasteur supporters, this 1877 paper by Pasteur was the definitive proof of bacterial causation of a mammalian disease.
For relevant Loeffler comment see Bert 1877.